Don't like that your Galaxy S6 conks out before you're finished for the day? Samsung might offer some relief in the future. Its scientists have developed lithium-ion battery technology that promises much longer-lasting power packs. They use a silicon anode (which promises much more capacity than a typical battery), but grow layers of graphene on top to improve the density and longevity that would otherwise suffer. In experiments, they got batteries that were 1.5 to 1.8 times denser than what you get today. If your smartphone barely makes it 12 hours before giving up the ghost, this would theoretically give you 21 hours -- enough that you wouldn't have to panic if you forgot to plug in before bedtime.